win32_waiter.h (2398B)
1 // Copyright 2023 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 16 #ifndef ABSL_SYNCHRONIZATION_INTERNAL_WIN32_WAITER_H_ 17 #define ABSL_SYNCHRONIZATION_INTERNAL_WIN32_WAITER_H_ 18 19 #ifdef _WIN32 20 #include <sdkddkver.h> 21 #endif 22 23 #if defined(_WIN32) && !defined(__MINGW32__) && \ 24 _WIN32_WINNT >= _WIN32_WINNT_VISTA 25 26 #include "absl/base/config.h" 27 #include "absl/synchronization/internal/kernel_timeout.h" 28 #include "absl/synchronization/internal/waiter_base.h" 29 30 namespace absl { 31 ABSL_NAMESPACE_BEGIN 32 namespace synchronization_internal { 33 34 #define ABSL_INTERNAL_HAVE_WIN32_WAITER 1 35 36 class Win32Waiter : public WaiterCrtp<Win32Waiter> { 37 public: 38 Win32Waiter(); 39 40 bool Wait(KernelTimeout t); 41 void Post(); 42 void Poke(); 43 44 static constexpr char kName[] = "Win32Waiter"; 45 46 private: 47 // WinHelper - Used to define utilities for accessing the lock and 48 // condition variable storage once the types are complete. 49 class WinHelper; 50 51 // REQUIRES: WinHelper::GetLock(this) must be held. 52 void InternalCondVarPoke(); 53 54 // We can't include Windows.h in our headers, so we use aligned character 55 // buffers to define the storage of SRWLOCK and CONDITION_VARIABLE. 56 // SRW locks and condition variables do not need to be explicitly destroyed. 57 // https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-initializesrwlock 58 // https://stackoverflow.com/questions/28975958/why-does-windows-have-no-deleteconditionvariable-function-to-go-together-with 59 alignas(void*) unsigned char mu_storage_[sizeof(void*)]; 60 alignas(void*) unsigned char cv_storage_[sizeof(void*)]; 61 int waiter_count_; 62 int wakeup_count_; 63 }; 64 65 } // namespace synchronization_internal 66 ABSL_NAMESPACE_END 67 } // namespace absl 68 69 #endif // defined(_WIN32) && !defined(__MINGW32__) && 70 // _WIN32_WINNT >= _WIN32_WINNT_VISTA 71 72 #endif // ABSL_SYNCHRONIZATION_INTERNAL_WIN32_WAITER_H_